1. Field of the Invention
The present invention relates to the field or couplers for railway vehicles and, more particularly, a railway coupler having mating cams to secure a coupled engagement between railway vehicles.
2. Description of Related Art
Railway vehicle couplers are used to securely couple adjacent railway vehicles. In a typical application, a coupler on one railway vehicle is aligned with a corresponding coupler on an adjacent railway vehicle. The two couplers interact to form a releasable connection between the adjacent railway cars. Each railway car desirably has a coupler provided at its longitudinal ends such that a plurality of railway cars may be coupled to form a train.
Within the prior art, conventional railway vehicle couplers may be operated via a chain or cable that utilizes a holding spring to act upon a toe of the coupling device. The holding spring is used to prevent unintended disengagement of the coupling device but also maintains the coupling device in a de-coupled orientation. Such a device is described in U.S. Pat. No. 325,923 to Ferguson.
In another design, U.S. Pat. No. 2,183,990 to Dunn discloses a coupling apparatus in which an over-center spring is used in association with a handle arm that is used to operate an eye element. In the coupled position of the coupler, springs pull on the handle arm and press the upper end of a pressure member rearwardly against the eye element to press the eye element against a hook to hold the eye element in engagement with the hook. In another prior art embodiment, U.S. Pat. No. 6,390,314 to Pinlam et al. discloses a trolley car clamp lock in which a locking engagement between a locking bar and a locking cantilever is secured by a locking bar spring and a locking cantilever spring.
Existing designs for railway vehicle couplers are associated with a number of disadvantages. Conventional railway vehicle couplers typically require precise alignment of railway vehicles to create a secure connection. Horizontal and vertical gathering angles of conventional railway vehicle couplers are relatively small, often allowing only a few degrees of vertical or horizontal misalignment. Additionally, existing railway vehicle couplers are not sufficiently robust to withstand repeated collisions between the couplers during coupling and uncoupling of railway vehicles.